Water-based adhesive

ABSTRACT

The present invention provides an organic solvent-free composition useful as an adhesive for bonding natural rubber compounds, synthetic rubber compounds and a combination of natural and synthetic rubber compounds.

This application is a continuation of application Ser. No. 08/470,915,filed Jun. 6, 1995, now abandoned, which is a division of 08/305,017filed Sep. 13, 1994, allowed which is a continuation-in-part applicationof application Ser. No. 08/180,679, now U.S. Pat. No. 5,395,879.

DETAILED DESCRIPTION OF THE INVENTION

The invention will now be described as embodied in several preferredembodiments.

Elastomers selected from the group consisting of natural rubber, styrenebutadiene rubber, polybutadiene rubber, polychloroprene rubber, nitrilerubber, polyurethane rubber, butyl rubber and mixtures thereof, may beemployed in the composition of the present invention. About 25.0 to50.0% of elastomer by total weight of the composition is required foroptimal adhesive properties.

The compositions of the present invention further comprise about 0.02 to0.60 weight percent pH adjusters selected from the group consisting ofpotassium hydroxide, aqueous ammonia and mixtures thereof.

The compositions of the present invention also comprise about 0.10 to1.8% surfactant/stabilizer selected from the group consisting of sodiumlignosulfate, octylphenoxypolyethoxyethanol, polyoxyethylene sorbitrolfatty acid ester, sulfated fatty acid and mixtures thereof.

The compositions of the present invention are manufactured by mixing pHadjusters water with the elastomer emulsion, using mild agitation. Thetotal water content is about 40 to 60 weight percent (by total weight ofthe composition).

Optionally, the compositions of the present invention may include up toabout 10.0% carbon black selected from the group consisting of N-300 andN-200 series (designations used in the adhesive industry for carbonblacks) and mixtures thereof.

The compositions of the present invention may also optionally include upto about 0.75% zinc oxide.

The compositions of the present invention may also optionally include upto about 0.40% sulfur.

The compositions of the present invention may also optionally include upto about 0.20% accelerator selected from the group consisting ofdibenzothiazyl disulfide, tetraethyl thiuram disulfide, tetramethylthiuram disulfide, tetramethyl thiuram monosulfide,n-tert-butyl-2-benzothiazolesulfenamide, diphenyl guanidine and mixturesthereof, is a critical component of the compositions of the presentinvention.

The compositions of the present invention may also optionally include upto about 0.50% viscosity adjusters selected from the group consisting ofhydroxyethyl cellulose, hydroxypropyl methylcellulose and mixturesthereof.

Lastly, the compositions of the present invention may also include up toabout 23% resin emulsion selected from the group consisting ofalkylphenol novolac, hydrogenated rosin and mixtures thereof.

Although the resulting aqueous adhesive may be used in tireapplications, it is recommended that the aqueous adhesive made withoutcarbon black be not used for tire applications. However, the aqueousadhesive made using carbon black may be advantageously applied to thebottom of an extruded tire tread and or to a carcass portion byspraying, dipping, brushing or flooding. After drying the adhesive, thetread is contacted with the carcass. The dried adhesive forms a thinlayer between the tread and carcass portion of the tire. Furtheroperations in the manufacture of the tire may be carried out in theusual manner.

The adhesive compositions of the present invention may also be used tobond tire tread ends to each other. However, in using the adhesives ofthe present invention in tire retreading, it has been found that boththe surfaces to be bonded to each other have to be coated with theadhesive. It has also been determined that the adhesives of the presentinvention are capable of being used with a greater variety of rubbersthan what is possible with the adhesives of parent application Ser. No.08/180,679. Polyester fibers, yams, filaments, cords or fabric may bebonded to vulcanizable rubber compounds by means of the compositions ofthe present invention, in order to prepare radial, bias or belted-biaspassenger tires, truck tires including the carcasses, belts, motorcycleand bicycle tires, off-the-road tires, transmission belts, V-belts,conveyor belts, hose, gaskets, rubbers tarpaulins and the like.

The invention will now be described as embodied in the following examplecompositions, wherein all percentages are by weight of the entirecomposition:

    ______________________________________               #1    #2      #3      #4    #5    ______________________________________    Water        44.53   54.67   46.39 54.59 48.95    Natural Rubber                 36.23   41.77   29.50 43.87 39.91    Carbon Black 0.51    2.69    6.81  --    0.56    Zinc Oxide   0.03    --      --    0.55  0.03    Sulfur       0.02    --      --    0.37  0.02    MBTS Accelerator                 0.01    --      --    0.20  0.01    Resin Emulsion                 18.41   --      15.55 --    10.13    Aqueous Ammonia                 0.02    0.10    0.26  0.04  0.02    Potassium Hydroxide                 0.03    0.02    0.02  0.04  0.02    Hydroxyethyl Cellulose                 0.10    0.24    0.17  0.13  0.23    Sodium Lignosulfate                 0.11    0.51    1.30  0.21  0.12                 100.0   100.0   100.0 100.0 100.0    Strip Adhesion (ppi)*                 94.0    96.0    120.0 92.0  91.0    ______________________________________     *ppi = pounds per inch (all showed rubber tear)

It has been discovered that carbon black is always required in tireretreading applications, as part of the solvent-free adhesive. Carbonblack may be dispensed with in non-tire applications, but in such anon-tire application, an accelerator is always required. The acceleratorspeeds the adhesion of uncured rubber on cured rubber by curing theuncured rubber.

Thus it is apparent that there has been provided, in accordance with theinvention, a composition useful as an adhesive for use with natural andsynthetic rubbers, which composition fully satisfies the aspects andadvantages set forth above. While the invention has been described inconjunction with specific embodiments thereof, it is evident that manyalternatives, modifications, and variations will be apparent to thoseskilled in the art in light of the foregoing description. Accordingly,it is intended to embrace all such alternatives, modifications andvariations which fall within the spirit and broad scope of the appendedclaims.

I claim:
 1. A composition having no organic solvents contained therein,said composition useful as an adhesive and comprising by weight percentbased on total weight of said composition:about 25.0 to 50.0% of anelastomer selected from the group consisting of natural rubber, styrenebutadiene rubber, polybutadiene rubber, polychloroprene rubber, nitrilerubber, polyurethane rubber, butyl rubber and mixtures thereof; about40.0 to 60.0% water; about 0.02 to 0.60% pH adjusters selected from thegroup consisting of potassium hydroxide, aqueous ammonia and mixturesthereof; about 0.10 to 1.8% surfactant/stabilizer selected from thegroup consisting of sodium lignosulfate, octylphenoxypolyethoxyethanol,polyoxyethylene sorbitol fatty acid ester, sulfated fatty acid andmixtures thereof; and from about 0.51 to 10.0% carbon black selectedfrom the group consisting of N-300 and N-200 series and mixturesthereof.
 2. An article of manufacture, having applied thereupon acomposition comprising by weight percent based on total weight of saidcomposition:about 25.0 to 50.0% of an elastomer selected from the groupconsisting of natural rubber, styrene butadiene rubber, polybutadienerubber, polychloroprene rubber, nitrile rubber, polyurethane rubber,butyl rubber and mixtures thereof; about 40.0 to 60.0% water; about 0.02to 0.60% pH adjusters selected from the from the group consisting ofpotassium hydroxide, aqueous ammonia and mixtures thereof; about 0.10 to1.8% surfactant/stabilizer selected from the group consisting of sodiumlignosulfate, octylphenoxypolyethoxyethanol, polyoxyethylene sorbitolfatty acid ester, sulfated fatty acid and mixtures thereof; and fromabout 0.51 to 10.0% carbon black selected from the group consisting ofN-300 and N-200 series and mixtures thereof.
 3. The article ofmanufacture of claim 2 being a rubber article made of natural orsynthetic rubber or a mixture of natural and synthetic rubber.
 4. Thearticle of manufacture of claim 3, wherein said composition furthercomprises up to about 0.50% viscosity adjusters selected from the groupconsisting of hydroxyethyl cellulose, hydroxypropyl methylcellulose andmixtures thereof.
 5. The article of manufacture of claim 3, wherein saidcomposition further comprises up to about 23.0% resin emulsion selectedfrom the group consisting of alkylphenol novolac, hydrogenated rosin,modified rosin ester and mixtures thereof.
 6. The composition of claim1, wherein said composition further comprises from about 0.03 to 0.75%zinc oxide; from about 0.02 to 0.40% sulfur; and from about 0.01 to0.20% accelerator selected from the group consisting of dibenzothiazyldisulfide, tetraethyl thiuram disulfide, tetramethyl thiuram disulfide,tetramethyl thiuram monosulfide,n-tert-butyl-2-benzothiazolesulfenamide, diphenyl guanidine and mixturesthereof.
 7. The article of manufacture of claim 2, wherein saidcomposition further comprises from about 0.03 to 0.75% zinc oxide; fromabout 0.02 to 0.40% sulfur; and from about 0.01 to 0.20% acceleratorselected from the group consisting of dibenzothiazyl disulfide,tetraethyl thiuram disulfide, tetramethyl thiuram disulfide, tetramethylthiuram monosulfide, n-tert-butyl-2-benzothiazolesulfenamide, diphenylguanidine and mixtures thereof.